/**
 * Copyright (c) 2016-present, Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "lstm_unit_op.h"

namespace caffe2 {
REGISTER_CPU_OPERATOR(LSTMUnit, LSTMUnitOp<CPUContext>);
OPERATOR_SCHEMA(LSTMUnit)
    .NumInputs(5)
    .NumOutputs(2)
    .SetDoc(R"DOC(
LSTMUnit computes the activations of a standard LSTM (without peephole
connections), in a sequence-length aware fashion.

Concretely, given the (fused) inputs X (TxNxD), the previous cell
state (NxD), and the sequence lengths (N), computes the LSTM
activations, avoiding computation if the input is invalid (as in, the
value at X{t][n] >= seqLengths[n].

)DOC")
    .Arg("forget_bias", "Bias term to add in while calculating forget gate");
REGISTER_CPU_OPERATOR(LSTMUnitGradient, LSTMUnitGradientOp<CPUContext>);
OPERATOR_SCHEMA(LSTMUnitGradient).NumInputs(9).NumOutputs(3);

class GetLSTMUnitGradient : public GradientMakerBase {
  using GradientMakerBase::GradientMakerBase;
  vector<OperatorDef> GetGradientDefs() override {
    return SingleGradientDef(
        "LSTMUnitGradient",
        "",
        vector<string>{I(0), I(1), I(2), I(3), I(4), O(0), O(1), GO(0), GO(1)},
        vector<string>{GI(0), GI(1), GI(2)});
  }
};
REGISTER_GRADIENT(LSTMUnit, GetLSTMUnitGradient);
}
